Orogenic plateau magmatism

Lead Research Organisation: Durham University
Department Name: Earth Sciences

Abstract

This study will show why some of the highest regions on Earth contain young and active volcanoes. Our particular study area is the high plateau of Iran, which has a unique combination of young volcanic rocks, known tectonic plate thickness and variation in plate thickness, in a region where the plates are actively colliding. Combined with background information on the rock types and thicknesses of the tectonic plates in this region, it will tell us which part of the deep Earth generates the magma, why it is melting, and what controls the ascent to the surface. Volcanoes and mountain ranges show how Earth is active: forces and processes arising from deep within the planet shape the landscapes on which we live. Risks from eruptions, earthquakes and landslides threaten millions of people, but at the same time control the distribution of land, nutrients and water on which we all depend. There are many ways to generate volcanoes and chains of mountains, some of which are entirely separate. But there are certain tectonic settings where they come together, where the moving plates collide continents to create vast regions of deformation known as collision zones. Many of these have occurred through geological time and are now inactive. The mountains of Scotland are the eroded roots of such chains, and the volcanoes once within their midst. But in SW Asia the processes continue at the present day, as the Arabian plate moves northward, pushing in to Eurasia. The rate of motion is roughly 20 mm/yr, but over geological timescales this translates to a considerable amount of deformation: ~700 km of convergence has occurred since initial plate collision ~35 million years ago. Volcanism was common before the collision, in a setting similar to the modern Andes. It reduced in intensity after the initial collision, because one of the main triggers for magmatism ended at this time - downgoing of oceanic plate beneath the Eurasian continent. Later, sporadic magmatism probably represented the tail-off from this process. But in the last few million years there has been an upsurge of volcanic activity across the collision zone, for reasons not entirely understood, but possibly related to a general re-organization of deformation of the Eurasian plate. The volcanic centres are not randomly distributed. We can determine patterns in their locations that give us clues about why the deep Earth is melting. First, they are concentrated in a region within the collision zone that is no longer shortening, known as the Turkish-Iranian plateau. As its name implies, this is a vast, high area with subdued relief, that no longer undergoes the kind of mountain building that once deformed the Earth in this area. That mountain building carries on at the margins of the broad zone that is the site of collision between the Arabian and Eurasian plates. Second, the volcanoes are almost always in the original Eurasian plate, which once lay above a slab of an oceanic plate that has now passed underneath it ('subducted' in the jargon). This slab is a source of water and other volatile compounds that could have been responsible for melting the deep Earth and causing the volcanoes. But it is unclear why water would be present tens of millions of years after the ocean plate stopped moving under Eurasia. Third, many of the volcanoes are located in regions which are still faulting, even if the mountains are not building up. This suggests a link between the faulting and either the generation of the magmatism, or at least its ascent to the surface. Again, the details are not understood and form part of this study. Whereas we generally understand the generation of volcanoes in settings like the Andes, Hawaii and Iceland, the high plateaux of the Earth like Iran and Tibet represent a frontier for science, and an opportunity to comprehend how the end result of plate tectonics can be volcanoes within the highest places on Earth.

Publications

10 25 50

 
Description We have developed a new model for the generation of volcanic rocks in regions where the continental plates continue to collide, using the geology of Iran and Armenia as guides. Our model involves the dripping of the base of the plate, and stirring of the underlying layer of the Earth, known as the mantle. In addition to this general model, we have produced significant data sets for specific volcanic centres in both Iran and Armenia. We have also looked at the uplift of the Andean Plateau, using data from volcanic rocks (lavas) to help estimate the rise of the Andes.
Exploitation Route Our research is generating high numbers of citations from other research groups across the world, showing that it has stimulated their thinking and their own research. It also feeds into the subject of which volcanic centres are active across these parts of the world, with implications for volcanic hazard.

Data have been fed into UN reporting on global volcanic hazards.

Discussions are in a preliminary stage about a new project, linking with Chinese researchers interested in similar themes.
Sectors Education,Environment

 
Description Findings have continued and strengthened the UK's academic links with Iran and Armenia, by demonstrating to scientists and government agencies from these countries that the UK can provide expertise, technologies and knowledge transfer to benefit their communities. There has been training for scientists in both of these countries in cutting edge techniques and analytical procedures, and integration into the wider international community via workshops and conference presentations in the UK and abroad. Help has been given all the way through to producing first-authored publications by these overseas colleagues, and involving them in other publications first-authored by the PI, PDRA or PhD students associated with the research. There has been input from Iranian project partners into the United Nations Office for Disaster Risk Reduction (UNISDR) Global Assessment Report for 2015 (GAR15), arising from contacts made through the project lifespan. This is a succinct example of how the project has improved scientific collaboration, with impacts on policy and decision making at international levels. These outcomes are examples of "soft power", by which the UK's expertise and goodwill are demonstrated in a subtle but positive way. The project PDRA has benefited from the training and development represented by the project, and now holds a teaching position in a UK university. An associated PhD student (EU funded) has gone on to a postdoctoral position in Finland.
Sector Education,Environment
Impact Types Cultural,Societal,Policy & public services

 
Description Iranian involvement in UN global hazard assessment
Geographic Reach Europe 
Policy Influence Type Participation in advisory committee
 
Description Durham University/COFUND Senior Research Fellowship
Amount € 21,965 (EUR)
Organisation Durham University 
Sector Academic/University
Country United Kingdom
Start 01/2016 
End 03/2016
 
Description GEF Travel grant scheme
Amount £1,900 (GBP)
Organisation Durham University 
Sector Academic/University
Country United Kingdom
Start 07/2014 
End 08/2014
 
Description University and EU Co-fund fellowship scheme
Amount £91,000 (GBP)
Organisation Durham University 
Sector Academic/University
Country United Kingdom
Start 09/2014 
End 08/2016
 
Title DEM processing for tectonic geomorphology 
Description Public domain Digital Elevation Models (DEMs) have been processed in Geographical Information Systems to quantify landscape evolution on tectonic plateaux. 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact Results are published in Allen et al (2013) (in the journal Tectonics) - one of the top 5% cited papers from this journal in 2013, which was also selected as an Editor's highlight for the year, and featured in two Physics/Geophysics magazines (EoS and Physics Today). 
 
Description Collision zone magmatism 
Organisation Geological Survey of Iran (GSI)
Country Iran, Islamic Republic of 
Sector Public 
PI Contribution Follow-up research on the theme of the NERC grant, and in essence continuing a collaboration that began in 2005. Current activities include a PhD proposal (to come under the NERC IAPETUS DTP scheme), and co-convening of an EGU conference session in 2015. A paper is in review, and others are in preparation or planned.
Collaborator Contribution Partners are providing samples, access to maps and other geological data, and technical input.
Impact Too early to report.
Start Year 2014
 
Description Collision zone magmatism - Armenia 
Organisation National Academy of Sciences of the Republic of Armenia
Country Armenia 
Sector Academic/University 
PI Contribution Like the Iranian example noted elsewhere, this is essentially a continuation of the NERC project's aims. The difference is that collaboration with Armenia colleagues only began in 2011
Collaborator Contribution Access to samples, maps and other data and fieldwork logistics.
Impact Too early to report.
Start Year 2011
 
Description AGU and EGU conference presentations 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Dissemination of results. Increased exposure to international science for colleagues from Armenia and Iran.

We have noticed high citation rates for some of our papers, which we partly attribute to this high level of conference activity. For example, Allen et al (2013) is the highest cited paper in the Journal of Petrology from 2013 (14 cites as of November 2014).
Year(s) Of Engagement Activity 2012,2013,2014
 
Description Celebrate Science Festivals 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Stimulated interest in Earth Sciences from general public. Raised awareness of natural hazards.

Festival audiences were ~5000 in 2012 and >7000 in 2014. Whilst it cannot be claimed that all these members of the public learned more about volcanoes and their compositions, many did.
Year(s) Of Engagement Activity 2012,2014
 
Description U3A talks 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact >200 members of the public reached in U3A presentations made in Bishop Auckland and Barnard Castle. More talks have been invited by other U3A groups in the region.

Stimulated audience interest in Iran
Year(s) Of Engagement Activity 2013,2014